Ports needed to see a computer in the Shared tab

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Level 2

220 points

Ports needed to see a computer in the Shared tab

I was wondering what ports need to be open to see a computer in the "Shared" section of the finder window. I realize Apple has an online list of what ports are needed for each protocol, but I do not know which protocol the "Shared" section is using to find the other computers.

I currently have the following ports open for tcp and udp...

22 (SSH)
139 and 445 (SMB)
548 (Appletalk)
3283 and 5900 (Apple Remote Desktop)

Any ideas?

2.4Ghz 15" MBP (LED) with 23" CinemaDisplay and 20" iMac G5 (revB), Mac OS X (10.5.1)

Posted on Jan 3, 2008 12:59 PM

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Answer 1

Best reply

Tim Haigh

Level 7

24,198 points

Jan 3, 2008 1:31 PM in response to Jeff Kearns

you may also nee mDNS multicast which runs on UDP 5353.

However shared server show up in my sidebar without opening those kind of ports. I just use the built in application firewall however.

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Answer 2

Jeff Kearns Author

Level 2

220 points

Jan 3, 2008 1:41 PM in response to Tim Haigh

I'll try 5353 as well.

My network has a hardware firewall that blocks all ports between computers except for those explicitly allowed... so this is independent of the MacOSX software firewall.

Is mDNS the only protocol that is used by the finder to populate the Shared section?

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Answer 3

Tim Haigh

Level 7

24,198 points

Jan 3, 2008 1:59 PM in response to Jeff Kearns

apple use a technology called bonjour formerly known as rendezvous. It uses mDNS.

This is what macs use to discover printers and other types of servers on your local network.

BTW a hardware firewall that is sophisticated enough to block tcp/udp traffic between local networked computers must also have the functionality for you to setup a trusted network and avoid this situation.

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Answer 4

Jeff Kearns Author

Level 2

220 points

Jan 3, 2008 4:25 PM in response to Tim Haigh

In addition to Bonjour, does the Service Location Protocol (port 427) do anything useful? The description lists it as used by the Network Browser.

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Answer 5

Snoop Dogg

Level 4

1,490 points

Jan 3, 2008 5:34 PM in response to Jeff Kearns

Service Location Protocol (SLP) has been dead for many years, and in Leopard it's completely gone. Bonjour (mDNS) uses port 5353 and the link-local multicast address 224.0.0.251.

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